Modern common rail injection systems generate multiple pulses, or “shots,” of fuel in each injection event. An ordinary practitioner will understand the general principles of how pre-burn and post-burn shots of fuel correlate to clean running engines, fuel economy, and reduced emissions. To optimize the performance of fuel injectors for multi-pulse injections, practitioners rely on testing fuel injectors using stand-alone testing machines which simulate fuel injector performance inside an operating engine. One type of fuel injection testing machine relies on cavitation to determine the time duration of a pulse of test fluid emitted from a fuel injector. The test fluid can be any type of fuel or other liquid capable of simulating fuel flowing through a fuel injector in an operating engine.
The development of multi-pulse common rail injection systems in which fuel injectors are actuated to provide pilot and/or post injections as well as the primary or main injection has prompted the need for new, end-of-the-line, functional test equipment that can measure the performance of the fuel injector.
It is known to connect a positive displacement system to a highly accurate electronic displacement measuring system, and these systems are sufficiently accurate to measure and test multi-pulse common rail injection systems. However, these systems are typically very complex and expensive. Consequently, such positive displacement, piston type measurement systems are not suitable for use in the manufacturing assembly line environment where numerous systems are required to test a significant number of fuel injectors.
An example of an alternative method to positive displacement includes a common-rail fuel injection rate measurement system consisting of a pressure chamber with pressure sensors, an amplifier box, an output processing unit, a data processing unit, and a volumetric flow-meter. These systems often include a back pressure sensor, a temperature sensor, a back pressure relief valve, and a discharge valve.
However, such known systems require complex processing and filtering of captured sensor output to derive information regarding the fuel injection quantity, variation, and/or rate shape. Such filtering and complex processing is necessary to remove the noise in the acquired data caused by the fuel pressure pulses reflected and propagating within the system.
Unfortunately, developing such extensive filters and processing methods is expensive. Furthermore, filtering and processing sensor output can decrease the accuracy of the system since the quality of the filters and methods used to process the sensor data can render the results inaccurate. Often, the resolution of the apparatus is not able to resolve the microsecond difference between the twin rate peaks of a multi-pulse common rail injection system.
More effective fuel injection testing machines are taught in U.S. Pat. No. 7,878,050 to Cueto and U.S. Pat. No. 7,975,535 to Cueto. The entire contents of each of these two patents are incorporated herein by this reference. Even though these machines greatly increase the efficiency of fuel injection testing, a common testing problem is that different manufacturers make fuel injectors with different dimensions, orientations, sizes, and shapes. Thus, testing injectors manufactured by different sources often requires the time-consuming and awkward task of adjusting the orientation of the fuel injection testing machine before running a test on certain injectors.
Therefore, what is needed is a surge chamber operably attached to a fuel injection testing machine and configured for quickly connecting to a fuel injector while accommodating the various sizes, shapes, and orientations of injectors made by different manufacturers.